1. Field of the Invention
The present invention relates to an irregular-surface (concave-convex surface) forming method using a plasma-etching process (plasma-etching treatment) and an electrode component. More particularly, the present invention relates to an irregular-surface forming method using a plasma-etching process, which is most suitable for forming an electrode component for electronic devices and the like, and the electrode component obtained by the forming method therefrom.
2. Description of the Related Art
Conventionally, a transparent electrode, that is, a thin film made from the metal oxide (hereinafter, it may be called as a metal oxide film) and formed by a method of a vapor deposition or the like on a glass plate, has been known.
However, a plastic film would substitute for a glass plate in view of the light weight and thinning down.
The following formation methods have been known to form a metal film or a metal oxide film on such a plastic film.
(1) A vapor deposition method such as the vacuum deposition or the sputtering and the like for a metal material and/or a metal oxide material.
(2) A coating method of the solution in which the metal particles or metal oxide particles were dispersed into an organic binder.
However, the production cost for the vapor deposition method (1), is expensive, since a high vacuum condition was necessary, and there are problems in mass productivity and economy.
Also, the coating method of the solution (2) had a problem that the conductivity of the obtained metal film and the like was inferior to that of the metal film and the like which was obtained by the vapor deposition method.
Accordingly, the metal oxide film forming method that the plasma process was carried out after having formed a metal oxide gel on a substrate by the sol-gel method using metal alkoxide and its hydrolyzate has been proposed (e.g., referring to the patent document 1).
More specifically, JP 2000-327310A was directed to the metal oxide film forming method, wherein the metal oxide gel on the substrate was beforehand obtained by changing a metal oxide sol that was obtained from the metal alkoxide or metal salt as a main raw material, and then a predetermined plasma process was carried out to the metal oxide gel to form the metal oxide film.
Meanwhile, in the technical field of an organic solar cell or the like, a transparent electrode substrate for a solar cell equipped with a texturing layer having the irregular-surface, in order to improve light conversion efficiencies, has been disclosed (e.g., referring to JP 2008-177549A).
More specifically, it was the transparent electrode substrate for a solar cell comprising a resin film, a texturing layer having the irregular-surface and a metal oxide layer, wherein the texturing layer having the irregular-surface is obtained by photo-curing of a photo-curable composition.
Furthermore, as an anodizing film, a method of forming a nanostructure pattern directly on a metal film or a metal oxide film has been proposed. Namely, the method for obtaining a porous material with a self-regularly property by using an electrochemical technique, has been proposed (e.g., referring to JP H2-254192A).
More specifically, as shown in FIG. 12A-FIG. 12F, it is the method for obtaining a porous material.
That is, as shown in FIG. 12A, an anodizing film (anodizing film barrier layer 202 and anodizing film porous layer 203) is formed on the surface by anodizing aluminum material which is set to be a matrix 201.
Next, as shown in FIG. 12B, the obtained anodizing film is used as the matrix 201, and a metal 205′ which is to be a negative mold of the porous film is filled in a pore of the matrix 201.
Further, as shown in FIG. 12C, the matrix 201 is selectively dissolved, and then, as shown in FIG. 12D, a negative mold 205 of the porous film is obtained by removing the anodizing films 202, 203.
Still further, as shown in FIG. 12E, the other material 206′ is filled into the negative mold 205.
Lastly, as shown in FIG. 12F, a porous material 206 which has the same shape as the anodizing film is obtained by selectively dissolving the negative mold 205.
However, according to the formation method disclosed in the patent document 1, the metal oxide sol had to be beforehand changed into the metal oxide gel, when forming the metal film or the metal salt film on the concave-convex structure. Namely, it should be changed before the plasma process was carried out to form the metal oxide film. Therefore, there were problems that not only many producing steps were necessary, but also it was difficult to stably and precisely form the metal oxide film on the concave-convex structure.
Also, according to the formation method disclosed in the patent document 2, there were problems that it was necessary to form the conductive layer comprising a metal film or a metal oxide film on the texturing layer having the concave-convex structure, and in addition that such a metal film or a metal oxide film easily exfoliated from the texturing layer.
Further, according to the formation method of the porous material disclosed in the patent document 3, there were problems that not only many producing steps were necessary, but also it was difficult to stably and precisely produce the porous material comprising the metal oxidize film.
On the other hand, it has been conventionally understood that the plasma-etching process could not be carried out to the substrate as groundwork, through the metal oxide material formed on the substrate.
Therefore, the present inventors have keenly studied the above mentioned problems, and they have discovered that relatively large irregular-surface could be stably and precisely formed on the substrate, by using the metal salt film having the fine irregular-surface which is partially oxidized, as a resist (an etching speed adjustment member), when carrying out the plasma-etching process to a substrate which is appropriate for an electrode component or the like, and they have accomplished to the present invention.
Namely, the objective of the present invention is to provide an irregular-surface forming method using the plasma-etching process to stably and precisely form the irregular-surface having the considerable big surface roughness on the substrate, and to provide an electrode component obtained by the irregular-surface forming method therefrom.